@@ -22,6 +22,7 @@ config X86
select HAS_PASSTHROUGH
select HAS_PCI
select HAS_PDX
+ select HAS_SCHED_GRANULARITY
select HAS_UBSAN
select HAS_VPCI if !PV_SHIM_EXCLUSIVE && HVM
select NEEDS_LIBELF
@@ -63,6 +63,9 @@ config HAS_GDBSX
config HAS_IOPORTS
bool
+config HAS_SCHED_GRANULARITY
+ bool
+
config NEEDS_LIBELF
bool
@@ -17,6 +17,7 @@
#include <xen/percpu.h>
#include <xen/sched.h>
#include <xen/sched-if.h>
+#include <xen/warning.h>
#include <xen/keyhandler.h>
#include <xen/cpu.h>
@@ -37,6 +38,83 @@ static DEFINE_SPINLOCK(cpupool_lock);
static enum sched_gran __read_mostly opt_sched_granularity = SCHED_GRAN_cpu;
static unsigned int __read_mostly sched_granularity = 1;
+#ifdef CONFIG_HAS_SCHED_GRANULARITY
+static int __init sched_select_granularity(const char *str)
+{
+ if ( strcmp("cpu", str) == 0 )
+ opt_sched_granularity = SCHED_GRAN_cpu;
+ else if ( strcmp("core", str) == 0 )
+ opt_sched_granularity = SCHED_GRAN_core;
+ else if ( strcmp("socket", str) == 0 )
+ opt_sched_granularity = SCHED_GRAN_socket;
+ else
+ return -EINVAL;
+
+ return 0;
+}
+custom_param("sched-gran", sched_select_granularity);
+#endif
+
+static unsigned int __init cpupool_check_granularity(void)
+{
+ unsigned int cpu;
+ unsigned int siblings, gran = 0;
+
+ if ( opt_sched_granularity == SCHED_GRAN_cpu )
+ return 1;
+
+ for_each_online_cpu ( cpu )
+ {
+ siblings = cpumask_weight(sched_get_opt_cpumask(opt_sched_granularity,
+ cpu));
+ if ( gran == 0 )
+ gran = siblings;
+ else if ( gran != siblings )
+ return 0;
+ }
+
+ sched_disable_smt_switching = true;
+
+ return gran;
+}
+
+/* Setup data for selected scheduler granularity. */
+static void __init cpupool_gran_init(void)
+{
+ unsigned int gran = 0;
+ const char *fallback = NULL;
+
+ while ( gran == 0 )
+ {
+ gran = cpupool_check_granularity();
+
+ if ( gran == 0 )
+ {
+ switch ( opt_sched_granularity )
+ {
+ case SCHED_GRAN_core:
+ opt_sched_granularity = SCHED_GRAN_cpu;
+ fallback = "Asymmetric cpu configuration.\n"
+ "Falling back to sched-gran=cpu.\n";
+ break;
+ case SCHED_GRAN_socket:
+ opt_sched_granularity = SCHED_GRAN_core;
+ fallback = "Asymmetric cpu configuration.\n"
+ "Falling back to sched-gran=core.\n";
+ break;
+ default:
+ ASSERT_UNREACHABLE();
+ break;
+ }
+ }
+ }
+
+ if ( fallback )
+ warning_add(fallback);
+
+ sched_granularity = gran;
+}
+
unsigned int cpupool_get_granularity(const struct cpupool *c)
{
return c ? sched_granularity : 1;
@@ -871,6 +949,8 @@ static int __init cpupool_init(void)
unsigned int cpu;
int err;
+ cpupool_gran_init();
+
cpupool0 = cpupool_create(0, 0, &err);
BUG_ON(cpupool0 == NULL);
cpupool_put(cpupool0);
Add a scheduling granularity enum ("cpu", "core", "socket") for specification of the scheduling granularity. Initially it is set to "cpu", this can be modified by the new boot parameter (x86 only) "sched-gran". According to the selected granularity sched_granularity is set after all cpus are online. A test is added for all sched resources holding the same number of cpus. Fall back to core- or cpu-scheduling in that case. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Dario Faggioli <dfaggioli@suse.com> --- RFC V2: - fixed freeing of sched_res when merging cpus - rename parameter to "sched-gran" (Jan Beulich) - rename parameter option from "thread" to "cpu" (Jan Beulich) V1: - rename scheduler_smp_init() to scheduler_gran_init(), let it be called by cpupool_init() - avoid using literal cpu number 0 in scheduler_percpu_init() (Jan Beulich) - style correction (Jan Beulich) - fallback to smaller granularity instead of panic in case of unbalanced cpu configuration V2: - style changes (Jan Beulich) - introduce CONFIG_HAS_SCHED_GRANULARITY (Jan Beulich) V4: - move code to cpupool.c --- xen/arch/x86/Kconfig | 1 + xen/common/Kconfig | 3 ++ xen/common/cpupool.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 84 insertions(+)